Sterilized laundry system

ABSTRACT

A sterilized laundry system utilizes a washing machine sealingly mounted in a common wall of a soiled area and a sterilized area and includes first and second door means respectively providing access from the soiled and the sterilized areas into an interior of a washing drum horizontally disposed within the washing machine, releasable locking means normally maintaining the pair of doors in a locked position and control means selectively releasing the locking means only to permit opening the doors in a manner to prevent cross infection between the separate rooms. The sterilized area is maintained at a constant positive pressure relative to the soiled laundry area and other areas ambient the sterilized room, thereby preventing flow of contaminated air into the sterilized area.

United States Patent lnventor Appl. No.

Filed Patented Assignee srenruzen LAUNDRY SYSTEM ll Claims, 3 Drawing Figs.

US. Cl

Int. Cl......

Field of Search References Cited UNITED STATES PATENTS 5/1967 Starr et al. .l

Primary Examiner-William i. Price Attorney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: A sterilized laundry system utilizes a washing machine sealingly mounted in a common wall of a soiled area and a sterilized area and includes first and second door means respectively providing access from the soiled and the sterilized areas into an interior of a washing drum horizontally disposed within the washing machine, releasable locking means normally maintaining the pair of doors in a locked position and control means selectively releasing the locking means only to permit opening the doors in a manner to prevent cross infection between the separate rooms. The sterilized area is maintained at a constant positive pressure relative to the soiled laundry area and other areas ambient the sterilized room, thereby preventing flow of contaminated air into the sterilized area.

STERILIZED LAUNDRY SYSTEM BACKGROUND OF THE INVENTION 1. Field ofthe Invention The present invention generally relates to commercial laundry equipment, and more particularly refers to a laundry system including means for delivering sterilized laundry persons or infected areas is prime source of the spread of bacteria throughout hospitals resulting in cross infection between patients. Thus, proper sanitary methods in the collection, transportation washing, and distribution of hospital linen will go a long way toward controlling incidence of cross infection. Proper distribution of sterilized laundry material requires that the sterilized laundry be completely isolated from contaminated areas subsequent to sterilization.

One form of commercial laundry equipment utilized for delivering sterilized laundry material and for preventing cross infection between soiled laundry and sterilized laundry includes a washing a washing machine sealingly mounted in a solid common wall separating a soiled laundry area from a sterilized laundry area and having a horizontally disposed, rotatably mounted washing cylinder or drum, Access to an interior of the washing drum is provided by a pair of doors respectively opening from the separate rooms. The washing machine is loaded through one door opening from the soiled area and unloaded from another door opening into the sterilized area.

To prevent cross infection between the soiled area and the sterilized area, the pair of doors providing access to the wash ing drum must be controllably locked in a manner to prevent simultaneously opening the doors or opening the sterilized room door until the laundry material has been sterilized. Prior art laundry systems have not included adequate, fail-safc means controlling means locking the separate doors in a manner to prevent cross infection.

Since bacteria may be easily transported by air currents, it is also necessary to provide means preventing flow of contaminated air from the soiled area or other areas either into the sterile area, or, subsequent to loading the machine, into the interior of the washing drum. Adequate airflow control means have not been proposed heretofore in the prior art.

SUMMARY OF THE INVENTION 'In accordance with the present invention, a washing system for assuring that soiled laundry material is properly sterilized and isolated from contaminated areas comprises a first area for receiving soiled laundry material, a second area completely isolated from the first area by a solid, common wall and a washing machine sealingly mounted in the common wall. To prevent contaminated air currents from flowing into the sterilized room, sterilized air under pressure is forced into the sterilized area to maintain that area at a positive pressure relative to ambient areas including the soiled laundry room. Since air may be sucked into the washing machine during the extraction cycle, a conduit opening directly into an interior of the washing machine supplies sterilized air at a pressure exceeding that of the soiled laundry room, but not exceeding the pressure of the sterilized laundry room. Thus, any leakage of flow of air will always be from the sterilized room to prevent contaminated air currents from entering that area.

The washing machine comprises a horizontally disposed, rotatably mounted washing cylinder or drum receiving the laundry material and means for washing, rinsing, extracting and sterilizing the laundry drawings, Laundry material is loaded into the drum through a first door means opening from the soiled laundry area into an interior of the washing drum, and the sterilized laundry material is unloaded from the washing drum through a second door opening at an opposite end of the washing machine and into the sterilized room. Locking means normally retaining both doors in a locked position are releasable in a controlled manner to assure that the sterilized room will not be exposed to contaminated laundry material or contaminated air currents.

Control means for releasing the door-locking means comprise means preventing simultaneous opening of the soiled room door and the sterilized room door to prevent direct exposure between the separated areas, means preventing release of the sterilized room door locking means until the washing machine has completed its washing cycle and the laundry material has been subjected to sterilizing temperatures for a sufficient period of time to prevent contaminated laundry material from inadvertently entering the sterilized room through the washing machine, and means preventing release of the soiled room door prior to unloading the sterilized material.

Since the total system partially depends upon maintaining the sterilized room at a positive pressure, the control means desirably include interlocking means preventing the sterilized room door from opening unless the forced air supply means is properly functioning.

Thus, the primary object of the present invention is to provide a laundry system for delivering sterilized laundry material and preventing contamination thereof by soiled laundry material.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

FIG. I is an end elevational view ofa washing machine embodying the features ofthe present invention:

FIG. 2 is a side elevational view of the washing machine of FIG. 1 and illustrating the machine mounted in a common wall separating a soiled laundry are a from a sterilized laundry area; and

FIG. 3 is a schematic drawing illustrating a control circuit embodying the features of the present invention and for controlling release of locking means normally retaining access doors of the washing machine in a lacked condition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, a laundry system constructed in accordance with the principles of the present invention comprises a soiled laundry area or room 10, a sterilized laundry area or room 11 sealingly separated from the soiled laundry room by a solid common wall 12, and a washing machine 13 sealingly mounted in the common wall so that the mechanical equipment thereof projects into the soiled laundry room. The machine 13 may be of the washer-extractor type and includes a sterilizing cycle wherein the laundry material is subjected to steam or water exceeding F. for a sufficient time interval to assure destruction of most bacteria and thus sterilization of the laundry material.

The washer 12 has an imperforate outer cylindrical housing or shell 14 extending on a horizontal axis between rectangularly shaped front and backplate members 16 and 17, respectively,. An airtight seal is formed between the front and backplates l6 and 17 and outer peripheral edges of end portions ofthe outer shell 14.

Situated within and disposed coaxially of the shell !11 is a washing cylinder or drum 18 in which soiled material to be laundered is deposited. A shaft 19 having opposite end portions thereofjoumaled in a pair of bearing blocks 21 and 22, respectively secured to the front plate 16 and the backplate 17 mounts the drum 18 for corotation therewith. The washing drum 18 comprises a foraminated cylindrical sidewall 23 and a pair of circular enclosures closing opposite ends of the cylindrical sidewall to form a closed drum. An interior of the washing drum 18 may be longitudinally divided into several separate compartments by substantially radially extending partitionsv During a washing operation, the drum 18 is rotated with the shaft 19 at tumbling speeds by means of an electric motor 24, and during an extracting operation the drum is rotated at a higher extracting speed by a relatively high-speed motor 26. Both motors 24 and 26 are supported or a shelf 27 which in turn is secured to the outer shell 14. THe cylinder shaft 19 is drivingly connected by a V-belt 28 to an auxiliary shaft 29 disposed parallel to, and laterally outwardly from, the cylinder shaft. The auxiliary shaft 29 is connected through a clutch and brake mechanism as at 31 and a multibelt drive as at 32 to the motors 24 and 26.

in order to provide access to the washing drum 18 for loading the machine 13 with soiled laundry material, the backplate 17 has an access opening 33 formed therein and a door 34 hinged at 36 and sealingly closable over the opening 33. Soiled laundry material is only loaded from the back or soiled room side and only unloaded from the front or sterile room side. Ac cess to the washing drum 18 for unloading purposes is provided through an access opening 35 formed in the front plate 16 and selectively closable by a hinged door 37. Each circular end closure of the washing drum 18 has openings in registry with each one of the individual separate compartments formed by the radially extending partitions, thereby providing ingress and egress means through which the laundry material is loaded into, and removed from, and interior of the washing drum 18. By jogging the washing drum 18, the openings for the individual compartments may be sequentially moved into registry with the corresponding opening 33 or 35 formed respectively in the backplate l6 and the front plate 17.

In order to seal an interior of the washing machine defined by interior surfaces ofthe outer shell 14, the front plate 16 and the backplate 17, seal means are provided between the hinged doors 34 and 37 and their associated openings 33 and 35, and door-securing means as at 39 securely clamp the doors 33 and 37 into sealing engagement with their respective end plates 16 and 17. Each door-securing means comprises a latch bar 41 and a screw means characterized by a threaded post 42 projecting outwardly from an associated one of the end plates 16 and 17 and loosely received in an aperture formed in the latch bar and a handwheel 43 threaded onto the post and abutting the latch bar. in a clamping position the latch bars 41 overlap offset portions as at 44 formed on the hinged doors 34 and 37 and the handwheels 43 are screwed onto the post a sufficient distance to tightly seal the access openings 33 and 35. The latch bars 41 may be released by backing the associated handwheel 43 off the threaded post 42 and rotating the latch bar to a noninterfering position.

To assure that the sterilized laundry material unloaded from the machine 13 remains uncontaminated after removal from the washing drum 18, it is necessary that the sterile room or area 11 be maintained in a sterile or uncontaminated condition. Thus, it is contemplated by the present invention, that the laundry system include means supplying the sterile room 11 with sterilized air under pressure to maintain that area at a positive pressure relative to ambient areas including the soiled laundry room 10, thereby causing any leakage of air between the sterile room 11 and the soiled laundry room to flow from the sterile area to the contaminated area for preventing contamination ofthe sterile area by airborne bacteria.

ln accordance with the principles of the present invention, the means supplying bacteriafree air to the sterile room 11 comprise a conduit or air duct 44 having a lower end portion as at 46 sealingly mounted in a complementarily shaped aperture 47 formed in a ceiling 48 of the room 11 and a fan 49 driven by an electric motor 51 and mounted within the air duct 44. An air purification device 52 is disposed within the duct 44 downstream of the forced air fan 49, thereby to sterilize air forced into the sterile room or area 11 by the fan.

During an extracting operation or cycle, air may be drawn into the machine, and if that air contains bacteria, the contents of the machine may be contaminated. Therefore, it is contemplated by the present invention to provide means for delivering sterilized air to the interior of the washing machine 13 during the operation thereof and for preventing flow of air from the soiled laundry room 10 to an interior of the washing machine 13 subsequent to starting the machine cycle. That means include a conduit or air duct 53 having a vertical portion 54 passing through a sealed aperture 56 in the ceiling 48 and a short horizontal section passing through a sealed aperture in the front plate 16 and terminating in the interior of the washing machine defined by the outer shell 14, the front plate 16 and the rear plate 17. Pressurized sterile air is forced through the duct 53 and into the interior of the washing machine, thereby supplying sterile air to replace air exhausted during the extracting operation and maintaining a positive air pressure relative to the pressure of the soiled laundry room 10 within the machine 13. Desirably, the pressure within the machine 13 is maintained in a range of pressures exceeding the pressure of the soiled laundry room 10 but less than the positive pressure within the sterile room 11. Thus, any flow of air currents due to leakage or otherwise will always be from the sterile room, to the interior of the washing machine and then to the soiled laundry room 10 or directly to the soiled laundry room 10. In that manner only bacteriafree air is delivered to the sterile room 11 and the interior of the washing machine 13, thereby preventing cross infection between the soiled laundry and the sterilized laundry by airborne bacteria.

Locking means 58 and 59 are provided respectively for the access doors 37 and 34 to normally lock the doors in a closed position. Each locking means may include a pneumatic cylinder as at 61, a piston or plunger 62 extending from, and axially slidable within, the cylinder, and a striker plate 63 characterized by an aperture for receiving an outermost end portion of the plunger. When the associated door 37 or 34 is sealed in a closed position by the securing means 39, the plunger 62 is aligned with the aperture of the striker plate 63 and will enter thereinto upon an increase in pressure at a rearward end of the cylinder 61, thereby locking the associated door in a closed position. On the other hand, increases in pressure on a forward end of the piston 61 causes the plunger 62 to retract into the cylinder 61 and withdraw from the striker plate 63 to unlock the associated door 37 or 34. Air supply to each of the pneumatic cylinders 61 of the locking means 59 and 58 are separately controlled by a pair of solenoidoperated air control valves forming a portion of a pneuma.ic control circuit of the machine 13.

If desired the pneumatic cylinder 61 may be replaced by an electrically operated solenoid having a plunger similar to the plunger 62 and functioning in a manner similar thereof in response to properly applied electric current.

In accordance with the principles of the present invention, control means are provided for controlling the locking means 58 and 59 respectively associated with the sterile room door 37 and the soiled laundry room door 34 so that the doors may not be inadvertently opened in a manner to contaminate the sterile room 11. As schematically illustrated in FIG. 3, a locking means control circuit 65 forming a portion of the overall circuit controlling various functions of the machine 13 comprises a solenoid 66 for unlocking the sterile room door locking means 58 whenever the solenoid 66 is energized and another solenoid 67 for unlocking the soiled laundry room door locking means 59 whenever the solenoid 67 is energized. A timing drum 68 driven by an appropriate timing motor controls an operating cycle of the machine and is connected to one side of a secondary coil of a transformer 69 supplying the control circuit 65 with 24-volt current.

The fan motor 51 driving the fan 49 to supply the sterile room 11 with forced air for maintaining that room at a positive pressure is connected in series with a manually operated fan switch 71. The fan switch 71 is mechanically interlocked with a switch 73 having a switch blade 74 and contact 75 and which in turn is connected in series with the unlocking solenoid 66, Thus, whenever the fan motor 51 is operating to supply sterile air to the sterile room 11, the switch 73 is closed.

After soiled laundry material is loaded into the washing drum 18, the soiled laundry room door 34 is closed and secured causing a portion of that door to engage and close a door interlock switch 76' electrically connected in series with the unlocking solenoid 66.

Situated within the machine 13 in a position to sense temperature of water drained from the washing drum 18 is a temperature sensitive switch 77 closing in response to sensing sterilizing temperatures, for example temperatures in excess of 180 F., present during a sterilizing cycle. When closed, the temperature-sensitive switch 77 energizes the relay coil 80 having normally open sets of contacts 81 and 82 and a normally closed set of contacts 83. The set of holding contacts 81,

disposed in parallel with the temperature-sensitive switch 77,

close in response to energization of the relay coil 80 to hold other means. With the relay coil 80 energized, the set of contacts 82, disposed in series with the unlocking solenoid 66, move to a closed position, whereas the normally closed set of contacts 83, connected in series with the unlocking solenoid 67 open to prevent actuation ofthe solenoid 67.

The timing drum 68 includes a switch means 1 momentarily closing upon completion of the machine cycle and connected in series with a relay coil 90 having normally open sets of contacts 91 and 92. Closing of the timing drum switch 86 energizes the relay coil 90 causing the normally open contacts 91 and 92 to close. The normally open contacts 91 connected in parallel with the switch 86 hold the relay coil 90 in an energized condition until that circuit is broken by other means. The normally open contacts 92 actuated by the relay coil 90 are connected in series with the unlocking solenoid 66 and close in response to completion of the machine cycle.

Thus, before the sterile room door unlocking solenoid 66 may be actuated, the fan 51 must be operating to close the mechanically interlocked switch 73, the laundry material must be subjected to sterilizing temperatures to close the normally open contacts 82, the machine cycle must be completed to close the normally open contacts 92 and the soiled laundry room door must be secured in a sealed position to close the door interlocked switch 76. When all of those conditions have been met, a sterile room door unlocking switch 93 may be moved to a closed position to complete the series circuit and thereby actuate the solenoid 66 to move the plunger 62 ol'the locking means 58 to an unlocked position. With the unlocking switch 93 in a closed position, an indicating light 94 located in the soiled laundry room lights to indicate to personnel in the soiled laundry room that the sterile room door 37 is unlocked.

Subsequent to unloading the sterilized laundry material from the machine 13, the sterile room door 37 is closed and secured. Once the door 37 is secured in a sealed position, the unlocking switch 93 is opened to deactuate the unlocking solenoid 66, thereby moving the plunger 62 of the locking means 58 into locking engagement with the aperture of the striker plate 63 mounted on the door 37. Closing and securing the door 37 causes a portion of that door to engage and close a door interlock switch 96 electrically connected in parallel with the unlocking solenoid 67.

Before the soiled laundry room door may be unlocked, the control circuit must be reset by momentarily closing a reset switch 97 to energize a relay coil 100 having normally closed contacts 101 and 102 connected respectively in series with the relay coils 80 and 90. Momentarily opening the normally closed contacts 101 and 102 deenergizes the relay coils 80 and 90 to move the sets of contact thereof to there normal position, nd in particular, to close the set of contacts 83 connected in series with the unlocking solenoid 67. Once the control circuit is reset, the unlocking solenoid 66 may not be opened until the machine has completed another cycle including a sterilizing operation.

With the control circuit reset and the door interlock switch 96 closed, a soiled laundry room door unlocking switch 103 may be closed, thereby, actuating the solenoid 67 to unlock the door 34 and enable the machine to be loaded with soiled laundry material.

From the foregoing description, it should be noted that once the laundry material has been subjected to sterilizing temperatures, the unlocking solenoid 67 controlling the soiled laundry room locking means 59 may not be actuated until the control circuit is reset. Thus once the laundry material has been sterilized it is impossible to expose the laundry material to the soiled laundry room 10 and then unload the laundry material into the sterile room 11 without first resterilizing the laundry material. That arrangement prevents contaminated laundry from entering the sterile laundry room and only permits sterilized laundry material to be unloaded from the machine 12 into the room 11. Also, whenever the fan motor 51 is not running to maintain the sterile room 11 at a positive pressure relative to ambient pressures, the sterile room door 37 may not be opened.

Although those versed in the art may suggest various minor modifications, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications which naturally and properly come within the scope of my contribution to the art.

lclaim:

1. A laundry system for preventing cross infection between soiled laundry material and sterilized laundry material comprising:

a washing machine having an interior chamber for receiving laundry material, first selectively lockable door means providing access in to the interior chamber from a soiled laundry area and a second selectively lockable door means providing access into the interior chamber for a second room area for receiving sterilized laundry materia];

first and second selectively releasable means respectively lacking said first and said second door means in closed positions;

means preventing release of said first locking means whenever said second door means is open; and

means. preventing release of said second locking means whenever said first door means is open and until said laundry material contained within the interior chamber has been subjected to sterilizing temperatures for a sufficient time period to assure proper sterilization.

2. The laundry system of claim 1 and further characterized by means preventing release of said second locking means until said machine completes a full washing cycle between releases thereof.

3. A laundry system as defined in claim 1 and further characterized by air distribution means forcing sterilized air into said second room area for maintaining said second room area at a positive pressure relative to said first room area.

4. A laundry system as defined in claim I and further characterized by duct means directing sterilized air under pressure into the interior chamber for maintaining the same at a positive pressure relative to said first room area.

5. A laundry system as defined in claim 3 and further characterized by means preventing release of said second locking means unless said air distribution means is properly functioning.

6. in a laundry system including a washing machine having first and second normally locked door means, a control circuit comprising:

first electrically actuated means for unlocking a first normally locked door means;

a second electrically actuated means for unlocking a second normally locked door means;

normally open, temperature-sensitive switch means disposed within an interior of a washing machine and closing in response to sensing sterilizing temperatures; and

first normally open contact means connected in series with said first unlocking means and closing whenever said temperature-sensitive switch means closes.

7. in a laundry system as defined in claim 6 and further characterized by second normally open contact means connected in series with said first unlocking means and closing in response to completion ofa washing machine cycle.

8. In a laundry system as defined in claim 7 and further characterized by normally closed contact means connected in series with said second unlocking means and opening whenever said temperature sensitive switch means closes.

9. in a laundry system as defined in claim 8 and further characterized by reset switch means for opening said first and said second normally open contact means and closing said normally closed contact means.

8 comprising:

first electrically actuated means for unlocking a first normally locked door means;

a second electrically actuated means for unlocking a second normally locked door means;

temperature sensitive switch means disposed within an interior of a washing machine and being actuated in response to sensing sterilizing temperatures; and

first circuit means electrically connected with said first unlocking means and permitting actuation thereofwhenever said temperature-sensitive switch means has been actuated.

11. A laundry system as defined in claim 1, wherein said means preventing release of said second locking means comprise temperature-sensitive means disposed in an interior chamber of a washing machine and permitting release of said second locking means only upon said temperature sensitive means sensing sterilizing temperatures within the interior 10. in a laundry system including a washing machine having Chamber first and second normally locked door means, a control circuit 

1. A laundry system for preventing cross infection between soiled laundry material and sterilized laundry material comprising: a washing machine having an interior chamber for receiving laundry material, first selectively lockable door means providing access into the interior chamber from a soiled laundry area and a second selectively lockable door means providing access into the interior chaMber for a second room area for receiving sterilized laundry material; first and second selectively releasable means respectively locking said first and said second door means in closed positions; means preventing release of said first locking means whenever said second door means is open; and means preventing release of said second locking means whenever said first door means is open and until said laundry material contained within the interior chamber has been subjected to sterilizing temperatures for a sufficient time period to assure proper sterilization.
 2. The laundry system of claim 1 and further characterized by means preventing release of said second locking means until said machine completes a full washing cycle between releases thereof.
 3. A laundry system as defined in claim 1 and further characterized by air distribution means forcing sterilized air into said second room area for maintaining said second room area at a positive pressure relative to said first room area.
 4. A laundry system as defined in claim 1 and further characterized by duct means directing sterilized air under pressure into the interior chamber for maintaining the same at a positive pressure relative to said first room area.
 5. A laundry system as defined in claim 3 and further characterized by means preventing release of said second locking means unless said air distribution means is properly functioning.
 6. In a laundry system including a washing machine having first and second normally locked door means, a control circuit comprising: first electrically actuated means for unlocking a first normally locked door means; a second electrically actuated means for unlocking a second normally locked door means; normally open, temperature-sensitive switch means disposed within an interior of a washing machine and closing in response to sensing sterilizing temperatures; and first normally open contact means connected in series with said first unlocking means and closing whenever said temperature-sensitive switch means closes.
 7. In a laundry system as defined in claim 6 and further characterized by second normally open contact means connected in series with said first unlocking means and closing in response to completion of a washing machine cycle.
 8. In a laundry system as defined in claim 7 and further characterized by normally closed contact means connected in series with said second unlocking means and opening whenever said temperature sensitive switch means closes.
 9. In a laundry system as defined in claim 8 and further characterized by reset switch means for opening said first and said second normally open contact means and closing said normally closed contact means.
 10. In a laundry system including a washing machine having first and second normally locked door means, a control circuit comprising: first electrically actuated means for unlocking a first normally locked door means; a second electrically actuated means for unlocking a second normally locked door means; temperature sensitive switch means disposed within an interior of a washing machine and being actuated in response to sensing sterilizing temperatures; and first circuit means electrically connected with said first unlocking means and permitting actuation thereof whenever said temperature-sensitive switch means has been actuated.
 11. A laundry system as defined in claim 1, wherein said means preventing release of said second locking means comprise temperature-sensitive means disposed in an interior chamber of a washing machine and permitting release of said second locking means only upon said temperature sensitive means sensing sterilizing temperatures within the interior chamber. 